While Meyer has several patents, many of them are not about HHO.

At least one patent describes breaking atomized water down using positively ionized air, with the unstated end result being a mixture of Nitrous-Oxide and Ammonia. (Ammonia is caustic, and will eat up metal, thus the reason for Meyer's spark-plug injectors injecting the combustible mixture into a cylinder full of freshly compressed air, resulting in an isolated pocket of combustible gasses.)

While having touched on the subject of positively ionized air, if both the air and HHO are both positively ionized, the valence electrons needed for covalent bonding are not available for the combustion process to complete, so until enough electrons migrate into the ignited mixture, combustion repeats and continues to give off more heat.

At least one patent exists for positively ionizing intake air for gasoline engines to gain power and mileage.

I have a document I'd like to post, but it's just over 500k, and it doesn't appear a file that large is allowed.